This invention relates to a locking means and especially for locking means for truck platform flaps.
In trucks having a load platform and flaps the load often gives rise to a considerable pressure from the inside against the flap, which entails the disadvantage that the appurtenant flap lock tends to become unintentionally opened. In locks of the prior art one has basically chosen between two ways when solving this problem. In cheaper locks a spring-loaded latch is utilized which maintains a locking handle in locking position. The handle may be freed by manual turning of the lock out of engagement, but this requires a considerable finger strength. It involves considerable difficulties to open the lock, particularly if it is subjected to a load on account of the pressure from the load against the flap. Another disadvantage of this known device resides therein that projecting parts of the lock may wear a tarpaulin or the like which convers the load platform to which the flap belongs. In addition hereto the projecting parts increase the effective dimensions of the load platform. In open position the handle often projects perpendicularly from the flap and the base plate and may then easily hit and damage a rear lamp or another fragile object when the flap is turned down.
The other way of solving the above problem has been to provide the lock with a latch bolt or slide which is displaceably mounted on the plate and forms a supplement to the locking yoke and in which the handle is pivoted. The handle is actuated in the direction towards its locking position by a torsion spring whose one end engages the handle and whose other end engages the latch bolt which in its locking position engages a U-shaped hook. The yoke is actuated in the direction towards its locking position (i.e. in the direction away from the free end of the handle when it occupies its locking position) by two compression springs which are mounted countersunk in the slide between a slide end wall and a pair of hooks provided on the base plate. A disadvantage of this solution is that the lock becomes rather complicated and comparatively expensive. Another drawback, of this solution is that the latch bolt tends to get stuck in its locking position through friction and possible pressure against the lock.